A burner of the species designed for single-fuel operation with liquid fuel is disclosed by German patent document no. 196 27 760 A1. This burner concept provides homogeneous distribution of an air-fuel mixture in the combustion space for the reduction of pollutant emissions. The divergent spray cone of an atomizer nozzle is directed onto an atomizer lip acting as an impact member at whose inside a fuel film moving downstream forms. The fuel film migrates up to an atomizer edge at the back end of the atomizer lip, where, due to an air guidance with two uniting airstreams (primary and secondary air streams) as well as a local cross-sectional constriction, it is subject to high shearing forces. The fuel film is especially finely and homogeneously atomized. The preferred application of this burner ensues in kerosene-operated aircraft gas turbines.
Stationary gas turbines are being employed to an increasing extent as rapidly connectible and disconnectible power machines in power plants for generating power, for example power for peak loads. Turbines capable of operation with gaseous fuel and with liquid fuel are being demanded more and more in view of a desire for unrestricted readiness to produce power. For example, natural gas is provided for "normal" operation and light heating oil is provided for an "emergency operation". Operating conditions can also occur where both fuels are simultaneously supplied. In addition to this specific application, a gas turbine having a "dual-fuel mode" can offer advantages in various burner applications.
A burner arrangement that can be optionally operated with liquid or gaseous fuel is already disclosed by German patent document no. 28 20 702 C2. In its center, this burner comprises a mixing ring with a mixing surface to which a spray fog of liquid fuel can be supplied with an air stream and from which the fuel-air mixture enters into the mixing ring. Gaseous fuel can be introduced in an air stream proceeding from the underside of the mixing ring. A column operation of both fuels is not provided.